no. 4
Invariant operators of inhomogeneous unitary group
Annales de l'I.H.P. Physique théorique, Tome 21 (1974) no. 4, pp. 341-345. 
@article{AIHPA_1974__21_4_341_0,
     author = {Rafique, M. and Tahir Shah, K.},
     title = {Invariant operators of inhomogeneous unitary group},
     journal = {Annales de l'I.H.P. Physique th\'eorique},
     pages = {341--345},
     publisher = {Gauthier-Villars},
     volume = {21},
     number = {4},
     year = {1974},
     zbl = {0303.17004},
     mrnumber = {372126},
     language = {en},
     url = {archive.numdam.org/item/AIHPA_1974__21_4_341_0/}
}
Rafique, M.; Tahir Shah, K. Invariant operators of inhomogeneous unitary group. Annales de l'I.H.P. Physique théorique, Tome 21 (1974) no. 4, pp. 341-345. http://archive.numdam.org/item/AIHPA_1974__21_4_341_0/

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